Prepend site.collections_dir if any.

_layouts/default.html

@@ -177,7 +177,7 @@ layout: table_wrappers
                   site.gh_edit_view_mode
                 %}
                   <p class="text-small text-grey-dk-000 mb-0">
-                    <a href="{{ site.gh_edit_repository }}/{{ site.gh_edit_view_mode }}/{{ site.gh_edit_branch }}{% if site.gh_edit_source %}/{{ site.gh_edit_source }}{% endif %}/{{ page.path }}" id="edit-this-page">{{ site.gh_edit_link_text }}</a>
+                    <a href="{{ site.gh_edit_repository }}/{{ site.gh_edit_view_mode }}/{{ site.gh_edit_branch }}{% if site.gh_edit_source %}/{{ site.gh_edit_source }}{% endif %}{% if page.collection and site.collections_dir %}/{{ site.collections_dir }}{% endif %}/{{ page.path }}" id="edit-this-page">{{ site.gh_edit_link_text }}</a>
                   </p>
                 {% endif %}
               </div>